1. Field of the invention
The present invention generally relates to an improved gap switch used as a starting switch of, for example, a pulse discharge type gas laser.
2. Description of the Prior Art
A gap switch and a thyratron with N.sub.2 gas (nitrogen gas) or SF.sub.6 (sulfur hexafluoride gas) enclosed in a tube have been known as a starting switch of a pulse discharge type gas laser.
However, although the former of the abovedescribed prior art apparatus has been simple in construction and handy, it has exhibited disadvantages in that it takes time to extinguish ions of the enclosed gas generated by an electric discharge. A breakdown also occurs at low voltages according to certain circumstances and, as a result, only the repeated operation at about 100 Hz can be practiced and it is difficult to repeat operations at high frequencies (hereinafter referred to as "operations repeated at high frequencies"). In addition, although the latter of the above-described prior art apparatus is mainly used for large-scaled laser discharging of a large electric current and has stable working characteristics, it is remarkably expensive and a separate power source for heating a filament is required and, as a result, it is unsuitable for a small-sized laser.
The present invention was achieved in view of the above-described matters. Thus, it is an object of the present invention to provide an inexpensive gap switch that is simple in construction and capable of repeating operations at high frequencies.